Stoichiometry of precipitation under conditions of double diffusion

Zivkovic, T Dragana; Pokrić, Biserka; Pučar, Z.

doi:10.1039/f19747001991

Cited by 10 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the critical precipitating concentrations are equimolar, and the "equivalency rule" demands equivalency at the onset of precipitation under conditions of diffusion [3,4,30,31 ], we may conclude that CaHPO4 is the first-formed precipitate at least in the phase of nucleation. This result does not imply that all phosphate in the buffer (pH 7.4) should be in HPO4"-ionic form; it indicates only that one calcium ion interacts with one phosphate ion during phase of nucleation.…”

Section: Precipitation Discsmentioning

confidence: 97%

Precipitation of calcium phosphates under conditions of double diffusion in collagen and gels of gelatin and agar

Pokrić

Pučar

1979

Calcif Tissue Int

View full text Add to dashboard Cite

One-dimensional double diffusion was applied to determine critical concentrations at which the precipitation of calcium phosphates occurs in reconstituted connective tissue collagen and agar gels at 37 degrees C and in gelatin gels at 25 degrees C. Experiments were performed in the presence of unbuffered 0.15 mol dm-3 NaCl, or 0.15 mol dm-3 NaCl-veronal adjusted to pH 7.4. It was found that critical concentrations of precipitation of both precipitating components, CaCl2 and phosphate buffer (pH 7.4), were equimolar and independent of the ratios of initial concentrations of the components. Critical concentrations of precipitation were not affected by the concentrations and kinds of gels used. The first-formed precipitates showed amorphous structure by X-ray diffraction analyses. Infrared (IR) spectra of the precipitates indicated CaHPO4 . H2O to be their predominant species. The molar Ca/P ratio obtained by chemical analyses was 1.08. This precipitate transformed in time into octacalcium phosphate. In all experiments, two very thin membranes of precipitate were formed in the gel column at the onset of precipitation simultaneously on both sides of the actual disc of precipitate. IR spectra and chemical analyses showed that both membranes were identical to the actual precipitation discs.

show abstract

Section: Precipitation Discsmentioning

confidence: 97%

Precipitation of calcium phosphates under conditions of double diffusion in collagen and gels of gelatin and agar

Pokrić

Pučar

1979

Calcif Tissue Int

View full text Add to dashboard Cite

show abstract

“…According to the ‘equivalency law’, the immunoprecipitation, under the diffusion conditions, occurs at the point where the ‘optimal’, i.e. the equimolar Ab/Ag proportions are reached (Živković et al., 1974). This means that the antigenic sites (epitopes) are completely occupied by the Abs (paratopes) and neither Ags nor Abs is present in excess in an IC prepared by the double immunodiffusion in a gel.…”

Section: Discussionmentioning

confidence: 99%

Immune Complex‐based Vaccine for Pig Protection against Parvovirus

Roić

Čajavec

Ergotić

et al. 2006

Journal of Veterinary Medicine, Series B

View full text Add to dashboard Cite

The insoluble immune complexes (ICs) were prepared under the conditions of double immunodiffusion in gel, using the suspension of the ultrasound treated PK-15 cell-line infected with porcine parvovirus (PPV) containing both viral particles and viral proteins, as well as pig or rabbit anti-PPV polyclonal immune sera. The immunodiffusion performed in an agarose gel allows only viral subunits with a molecular mass equal to or less than 1000 kDa, rather than the viral particles, to diffuse through the gel and reach the point where the immunoprecipitate is to be formed. The immunoprecipitation under the conditions of the diffusion ensures the optimal, i.e. equimolar ratio of both immunoprecipitating components, antibody/antigen in the IC. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the Western blot analyses showed the ICs were composed of two proteins, a protein in which molecular mass corresponded to the VP2 of the PPV and a protein with a molecular mass of the IgG. This suggests that the ICs are mainly composed of the VP2 antigen and IgG class antibodies. The potency of the IC-vaccines prepared in the form of a water-in-oil-in-water emulsion was compared with that of a commercially available, inactivated oil vaccine. The vaccination of gilts, 6 weeks before mating, with the IC containing allogeneic pig antibodies, resulted in the development of high and long-lasting anti-PPV antibody titres, similar to those generated by the licenced vaccine (P > 0.01). The content of the virus material administered by the IC was twice lower than that in the licenced vaccine. Neither systemic nor local reactions were observed in the gilts during the period of the trial with the IC vaccine. The number of viable piglets per litter varied between 9 and 12 and no signs of the PPV infection were detected. Rabbits were used as one of the alternative laboratory animal models accepted for the testing of the vaccine against the PPV. The rabbit humoral immune response generated by the IC containing the allogeneic antibodies were higher than that generated by the ICs containing the xenogeneic pig antibodies. It was similar to that generated by two-times higher content of the virus material administered by a commercially available vaccine. The IC-based vaccines belong to non-replicating, subunit vaccines, which are both ecologically convenient and the safest vaccines of all.

show abstract

“…According to the equivalence rule, the precipitation under conditions of a double diffusion starts at the equivalent molar concentrations of both precipitating components, ,− as indicated by eq 2: …”

Section: Theoretical Considerationsmentioning

confidence: 99%

Precipitation at Equivalence and Equilibrium: A Method for the Determination of Equilibrium Constants of Reaction between Multideterminant Antigen and Specific Polyclonal Antibodies

Pokrić

2000

J. Chem. Inf. Comput. Sci.

Self Cite

View full text Add to dashboard Cite

A theoretical approach for the determination of the equilibrium constant, Ka, of the reaction between a multideterminant antigen (Ag) and specific polyclonal antibodies (Ab) forming the insoluble Ab/Ag immune complex, is derived. The constant can be expressed as a function of the two accessible experimental parameters, the precipitating concentration of the antigen and the Ab/Ag molar ratio. For this purpose Ab/Ag immune complex must be prepared at equivalence, and equilibrium between precipitated and soluble species must be reached. The proposed method is experimentally tested on the system human serum albumin (HSA) and polyclonal rabbit antibodies. The Ab/Ag precipitates are prepared by the direct mixing of biological fluids in which immunoreacting components naturally occur. Previous separation, purification, or labeling of immunoreacting components are not required. The conditions for the precipitation of Ab/Ag complexes at equivalence, the stoichiometric composition or the average number of Ab molecules bound to one Ag molecule, and the solubility of the immunoprecipitating components are determined by a rectangular two-dimensional double immunodiffusion. Since the solubility determined under the conditions of a double immunodiffusion is a result of the interaction of the global diffusion of the precipitating components and particle growth kinetics, it mostly refers to the dynamic conditions. To find the solubility under equilibrium conditions, it is sufficient to determine the minimal factor by which the solutions of both immunoprecipitating components should be diluted so that no precipitate is formed upon their mixing at equivalence. The dilution factor is determined by a measurement of the laser light scattering of the immunoprecipitating systems prepared with serially diluted Ag and Ab solutions.

show abstract

Stoichiometry of precipitation under conditions of double diffusion

Cited by 10 publications

References 0 publications

Precipitation of calcium phosphates under conditions of double diffusion in collagen and gels of gelatin and agar

Precipitation of calcium phosphates under conditions of double diffusion in collagen and gels of gelatin and agar

Immune Complex‐based Vaccine for Pig Protection against Parvovirus

Precipitation at Equivalence and Equilibrium: A Method for the Determination of Equilibrium Constants of Reaction between Multideterminant Antigen and Specific Polyclonal Antibodies

Contact Info

Product

Resources

About